000 
FXUS65 KTFX 161541
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
941 AM MDT THU JUL 16 2009

.UPDATE...
FORECAST SOUNDINGS INDICATE WEAK INSTABILITY OVER MOST OF THE
FORECAST AREA THIS AFTERNOON. HOWEVER MOISTURE AND DECENT LIFT ARE
LIMITED. STILL MODELS TEND TO GENERATE SOME CONVECTION IN THE
NORTH POSSIBLY ASSOCIATED WITH A WEAK SHORTWAVE. HAVE DECIDED TO
ADD ISOLATED THUNDERSTORMS THIS AFTERNOON IN THAT AREA. ALSO WILL
ADD SOME ISOLATED THUNDERSTORMS THIS AFTERNOON OVER GALLATIN
COUNTY TO MATCH UP WITH BILLINGS WEATHER OFFICE. REMAINDER OF THE
FORECAST LOOKS ON TRACK. BLANK

&&

.AVIATION...
UPDATED 1132Z.
AN UPPER LEVEL HIGH PRESSURE RIDGE WILL CONTINUE TO BUILD AND THE 
AIRMASS WILL REMAIN QUITE DRY. WEAK INSTABILITY WILL DEVELOP THIS 
AFTERNOON BUT THE LACK OF MOISTURE WILL RESTRICT THE DEVELOPMENT OF 
THUNDERSTORMS. VFR CONDITIONS WILL PREVAIL DURING THE NEXT 24 HOURS. 

&&

.PREV DISCUSSION...
/ISSUED 532 AM MDT THU JUL 16 2009/

TODAY THROUGH SATURDAY...STRONG UPPER RIDGE CONTINUES TO BUILD OVER
THE REGION KEEPING THE AREA WARMER AND DRIER. A SHORTWAVE WILL
AFFECT THE NORTHERN ZONES TODAY. SOME WEAK INSTABILITY AS A RESULT OF
THIS MAY CAUSE AN ISOLATED SHOWER OR TWO OVER NORTH CENTRAL
MONTANA THIS AFTERNOON. ON FRIDAY AND SATURDAY THERE WILL BE SOME WEAK
INSTABILITY OVER SW MONTANA BUT NOT MUCH MOISTURE OR LIFT SO HAVE
NOT INCLUDED SHOWERS AT THIS TIME. TEMPERATURES WILL GENERALLY BE
IN THE 80S WITH PLACES IN NORTHEAST MONTANA BREAKING INTO THE 90S.

SATURDAY NIGHT THROUGH TUESDAY NIGHT...THE UPPER LEVEL HIGH PRESSURE 
RIDGE WILL BE OVER EASTERN MONTANA BY SATURDAY NIGHT. TO THE 
WEST...A LOW PRESSURE TROF WILL APPROACH THE WEST COAST. THIS LOW 
PRESSURE TROF WILL BE OVER THE PACIFIC NORTHWEST SUNDAY AND HEIGHTS 
ALOFT WILL BE FALLING ACROSS THE ZONES. WEAK INSTABILITY WILL 
DEVELOP SUNDAY AFTERNOON ALTHOUGH MOISTURE WILL REMAIN SPARSE. THE 
BEST CHANCE OF CONVECTION WILL BE OVER SOUTHWEST MONTANA AND WITH 
DRY LOW LEVELS...STRONG GUSTS WILL BE POSSIBLE. THE RIDGE WILL BEGIN 
TO REBUILD MONDAY AND THE AIRMASS WILL GRADUALLY WARM AGAIN. TEMPS 
WILL BEGIN THE PERIOD SUNDAY ABOVE NORMALS BUT DROP TO NEAR NORMALS 
MONDAY AS THE AIRMASS COOLS WITH TROF PASSAGE. TEMPS WILL BEGIN TO 
TREND UPWARDS AGAIN TUESDAY. ZELZER 

WEDNESDAY AND THURSDAY...A HIGH PRESSURE RIDGE IS EXPECTED OVER 
MONTANA THROUGH THIS PERIOD. A SLIGHT CHANCE FOR ISOLATED SHOWERS 
AND THUNDERSTORMS FOR THE NORTH CENTRAL PLAINS AS PERIODIC 
DISTURBANCES MOVE THROUGH THE WEST TO NORTH WEST FLOW. TEMPERATURES 
WILL BE NEAR SEASONAL AVERAGES FOR MUCH OF THE REGION. SAUCIER

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  85  54  87  55 /   0   0   0   0 
CTB  80  51  82  51 /  10  10   0   0 
HLN  88  56  91  56 /   0  10   0   0 
BZN  89  49  91  52 /   0  10   0  10 
WEY  80  42  83  44 /  10   0  10  10 
DLN  82  52  83  54 /   0   0  10  10 
HVR  85  53  90  54 /  10  10   0   0 
LWT  82  51  85  51 /   0  10   0   0 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BLANK
LONG TERM...SUK
AVIATION...SUK

WEATHER.GOV/GREATFALLS